Stem cells are defined by the NIH as unspecialized cells that can
self-renew over long periods of time through cell division, and,
under certain conditions, can be induced to become specialized
cells. Both embryonic
and adult (or somatic) stem cells are being researched for their
therapeutic potential. This month, Special Topics examines the
subject of stem cells over the past decade and the past two years.
The 20 most-cited papers on stem cells over the past decade
include 17 original articles and three review papers. The
overwhelming theme of the list appears to be the hematapoeitic
potential of embryonic and adult stem cells. Among the possible
types of cells into which stem cells can differentiate are liver
cells, bone marrow cells, blood cells, cardiac muscle cells, and
vascular endothelium. One paper shows the successful use of stem
cells for bone marrow engraftment. Another looks at the incidence of
invasive fungal infections in patients who have had stem cell bone
marrow engraftment. Finally, one paper debates the developmental
plasticity of adult stem cells vs. embryonic cells.
The two-year list consists of 18 original articles and two review
papers. Studies on the regulation of stem cells dominate this list
and include Wnt and Notch signal pathways, the SLAM family of
receptors, and polycomb group proteins. Gene expression profiles of
stem cells are also discussed, as are the identification of
bronchioalveolar stem cells in normal lung tissue and lung cancer,
road maps for blood lineage commitment, and the function of
mesenchymal stem cells. One paper details a double-blind, randomized
controlled trial of 67 post-myocardial-infarction patients that
examined the effects of autologous bone-marrow-derived stem cell
transfer on the infarct-related artery. Another paper describes the
generation of a functional mammary gland from a single stem cell.
Methodology
To construct this database,
papers were extracted based on title-supplied keywords for Stem Cells. The keywords used were as follows:
stem cell*
The baseline time span for this database
is 1997-June 30, 2007. The resulting database contained 16,536 (10 years)
and 6,689 (2 years) papers; 47,509 authors;
75 countries; 1,587 journals; and 7,223 institutions.
Rankings
Once the database was in place,
it was used to generate the lists of top 20 papers (two- and ten-year
periods), authors, journals,
institutions, and nations, covering a time span of 1997-June 30, 2007 (third bimonthly, a 10-year plus
6-month period).
The top 20 papers are ranked
according to total cites. Rankings for author, journal, institution,
and country are listed in three ways: according to total cites, total
papers, and total cites/paper. The paper thresholds and corresponding
percentages used to determine
scientist, institution, country, and journal rankings according to
total cites/paper, and total papers respectively are as follows:
| Entity: |
Scientists |
Institutions |
Countries |
Journals |
| Thresholds: |
17 |
83 |
25 |
19 |
| Percentage: |
1% |
1% |
50% |
10% |
